Castle Island Weather Forecast

    • 43
    • 56

    Decreasing Clouds

    • 42
    • 51

    Mostly Sunny

    • 43
    • 52

    Mostly Sunny

    • 44
    • 54

    Mostly Sunny

    • 45
    • 55

    Partly Sunny

    • 45
    • 53

    Mostly Cloudy

Today 6 Apr San Juan County

Mostly sunny. Highs near 60. Light wind becoming south 10 to 15 Mph with Gusts to 25 Mph in the afternoon.

Tonight 6 Apr San Juan County

Partly cloudy. Lows in the upper 30s to mid 40s. West wind 10 to 20 Mph with Gusts to 30 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Castle Island Temperature Statistics

April Temperature

Whidbey Island Naval Air Station - Ault Field (8.1 miles)

  • Lowest 2 April, 2026

    43 °F

  • Average April

    47.7 °F

  • Highest 3 April, 2026

    57 °F

Climate (2021–Present)

Whidbey Island Naval Air Station - Ault Field (8.1 miles)

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  • Average Low 2021–2026

    44.5 °F

  • Average 2021–2026

    50.1 °F

  • Average High 2021–2026

    56.1 °F
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